National Geographic : 2014 Oct
48 national geographic • october 2014 stages of developing genetically modified cassava varieties that are immune to the brown streak virus. Taylor is collaborating with Ugandan re- searchers on a field trial, and another is under way in Kenya. But only four African countries—Egypt, Sudan, South Africa, and Burkina Faso—current- ly allow the commercial planting of GM crops. In Africa, as elsewhere, people fear GM crops, even though there’s little scientific evidence to justify the fear. There’s a stronger argument that high-tech plant breeds are not a panacea and maybe not even what African farmers need most. Even in the United States some farmers are having problems with them. A paper published last March, for instance, documented an unsettling trend: Corn root- worms are evolving resistance to the bacterial toxins in Bt corn. “I was surprised when I saw the data, because I knew what it meant—that this technology was starting to fail,” says Aaron Gassmann, an entomologist at Iowa State Uni- versity and co-author of the report. One prob- lem, he says, is that some farmers don’t follow the legal requirement to plant “refuge fields” with non-Bt corn, which slow the spread of resistant genes by supporting rootworms that remain vulnerable to the Bt toxins. In Tanzania there are no GM crops yet. But some farmers are learning that a simple, low- tech solution—planting a diversity of crops—is one of the best ways to deter pests. Tanzania now has the fourth largest number of certified organic farmers in the world. Part of the credit belongs to a young woman named Janet Maro. Maro grew up on a farm near Kilimanjaro, the fifth of eight children. In 2009, while still an undergraduate at the Sokoine University of Agriculture in Morogoro, she helped start a non- profit called Sustainable Agriculture Tanzania (SAT). Since then she and her small staff have been training local farmers in organic practices. SAT now receives support from Biovision, the Swiss organization headed by Hans Herren. Morogoro lies about a hundred miles west of Dar es Salaam, at the base of the Uluguru Moun- tains. A few days after my visit with Juma in Bagamoyo, Maro takes me into the mountains to a minimum of 15 years to do this,” Quick says. “We’re in year four.” If they succeed, the same techniques might help enhance the productivity of potatoes, wheat, and other C3 plants. It would be an unprecedented boon to food security; in theory yields could jump by 50 percent. Prospects like that have made Zeigler a pas- sionate advocate of biotechnology. White- bearded and avuncular, a self-described old lefty, Zeigler believes the public debate over geneti- cally modified crops has become horribly mud- dled. “When I was starting out in the ’60s, a lot of us got into genetic engineering because we thought we could do a lot of good for the world,” he says. “We thought, These tools are fantastic! “We do feel a bit betrayed by the environmen- tal movement, I can tell you that. If you want to have a conversation about what the role of large corporations should be in our food supply, we can have that conversation—it’s really impor- tant. But it’s not the same conversation about whether we should use these tools of genetics to improve our crops. They’re both important, but let’s not confound them.” Zeigler decided on his career after a stint as a science teacher in the Peace Corps in 1972. “When I was in the Democratic Republic of the Congo, I saw a cassava famine,” he says. “ That’s what made me become a plant pathologist.” Which vision of agriculture is right for the farmers of sub-Saharan Africa? Today, says Nigel Taylor, a geneticist at the Donald Danforth Plant Science Center in St. Louis, Missouri, the brown streak virus has the potential to cause another cas- sava famine. “It has become an epidemic in the last five to ten years, and it’s getting worse,” he says. “With higher temperatures, the whitefly’s range is expanding. The great concern is that brown streak is starting to move into central Africa, and if it hits the massive cassava-growing areas of West Africa, you’ve got a major food-security issue.” Taylor and other researchers are in the early “ We do feel a bit betrayed by the environmental movement, I can tell you that.” –Robert Zeigler The magazine thanks The Rockefeller Foundation and members of the National Geographic Society for their generous support of this series of articles.